Automatic lock mechanism for bar clamp

ABSTRACT

A bar clamp includes a forward gripping section having two jaws, a rear housing, and an interconnecting tube. Pressing back a trigger handle will cause the jaws to grip an article, and counterclockwise pivot a link to cause a lock member to move through an opening of a locking plate into a slot of a release member. The article is gripped permanently after releasing the trigger handle by lockingly engaging a top of the lock member with an upper face of the opening. Counterclockwise pivoting a release lever will disengage the lock member with the opening, release a stored elastic force and apply same to the trigger handle for clockwise pivoting, and move one jaw away from the other jaw for dropping the article.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to bar clamps and more particularly to abar clamp having an improved lock mechanism, the bar clamp being adaptedto operate by a single hand for gripping an article (e.g., one beingdifficult of accessing or unwilling to access by the hand(s)) andautomatically locking same even after the hand releasing the grippedarticle.

2. Related Art

In many contexts (e.g., in hospitals), persons (e.g., medical workers)may have difficulties of accessing an article or are unwilling to accesssame by the hand(s) due to potential contamination. Thus, a person mayuse a clamp (e.g., bar clamp) to grip the article.

Typically, a bar clamp has an elongate bar, two front jaws, and a rearpistol-shaped lock section including a handgrip and a trigger handle. Inuse, one hand grips the handgrip and the trigger handle and presses backthe trigger handle to activate the jaws in order to grip an article.Next, slide a release level to a locked position so as to continuouslygrip the article. Finally, slide the release level to an unlockedposition for releasing the article for subsequent treatment.

However, the prior art bar clamp suffered from a disadvantage. Forexample, a person is prone to loosening the gripping by the hand aftergripping the article by the jaws. Unfortunately, the gripped article maydrop if it has not been locked (i.e., the bar clamp does not lock thegripped article automatically). In brief, the prior art bar clampcontradicts the habit of using same by ordinary people. Thus, a need forimprovement exists in order to overcome the inadequacy of the prior artand contribute significantly to the advancement of the art.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a barclamp having a unique and novel lock mechanism which is operable to lockan article gripped by jaws automatically even after the hand grippingthe article is loosened. For releasing the article, the user may slide arelease lever to an unlocked position.

To achieve the above and other objects, the present invention provides abar clamp comprising a gripping section including two pairs of first armand second arm formed of an elastomeric material, and two jaws eachformed at one ends of either pair of first arm and second arm; a tubefor receiving portions of the first arms and including a forward chucksecured to the other ends of the first arms; and a housing including aforward channel with a rear portion of the tube secured therein, acurved groove, a handgrip, a pivotal trigger handle, a pivotal releasemember including two laterally projecting release levers, a hooked base,and an intermediate slot between the release levers, a connecting memberin the rear portion of the tube and having one end secured to the otherends of the first arms and the other end projected rearward to secure toan intermediate portion of the trigger handle, a rectangular lockingplate having a top retained in the groove and a bottom retained in thebase, the locking plate including an intermediate opening, and a linkhaving one end secured to the intermediate portion of the trigger handleand including a rear curved lock member; whereby pressing back thetrigger handle will counterclockwise pivot the trigger handle to pullthe connecting member and the second arms with an elastic force storedin the second arms, move pairs of first arm and second arm toward eachother until an article is gripped by the jaws, and counterclockwisepivot the link to cause the lock member to move through the opening intothe slot wherein the article is gripped permanently after releasing thetrigger handle by lockingly engaging a top of the lock member with anupper face of the opening; and counterclockwise pivoting the releaselever will counterclockwise pivot a bottom of the locking plate aboutthe groove, disengage the top of the lock member with the upper face ofthe opening, release the elastic force and apply same to the triggerhandle to clockwise pivot both the link and the trigger handle, and pushthe connecting member and the pairs of second arm to move one pair offirst arm and second arm away from the other pair of first arm andsecond arm for dropping the article.

In one aspect of the present invention the lock member is a bifurcationincluding two branches, and the opening comprises two holescorresponding to the branches for either allowing the branches to freelypass or lockingly retaining same therein.

In another aspect of the present invention a top of either branch has anuneven surface.

The above and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptiontaken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of a preferred embodiment of bar clampaccording to the invention;

FIG. 2 is a longitudinal sectional view of the rear lock section;

FIG. 3 is a longitudinal sectional view of the housing of the locksection;

FIG. 4 is a longitudinal sectional view of the trigger handle;

FIG. 5 is a perspective view of the sliding member;

FIG. 6 is a side elevation of the link;

FIG. 7 is a perspective view of the locking plate;

FIG. 8 is a perspective view of the release member;

FIG. 9 is a longitudinal sectional view of the locking plate;

FIG. 10 schematically depicts movement of the locking plate in the locksection in an unlocking operation; and

FIG. 11 is a longitudinal sectional view of the locking plate locked bythe curved members of the link.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a bar clamp in accordance with a preferredembodiment of the invention comprises a rear lock section 10, anintermediate tube 20, and a front gripping section 30. Each component isdiscussed in detailed below.

The lock section 10 comprises a housing 11 of pistol shape, a triggerhandle 12, and a release member 13. The tube 20 comprises a forwardchuck 21. The gripping section 30 comprises two pairs of first arm 31and second arm 32, and two cup-shaped jaws 33 each formed at open endsof either pair of first arm 31 and second arm 32.

The chuck 21 is adapted to fasten the proximal ends of the first arms31. The other ends of the second arms 32 are secured to one end of aconnecting member 14 (see FIG. 2) in a rear of the tube 20. The otherend of the connecting member 14 is secured to the trigger handle 12 asdetailed later.

Each of the first and second arms 31 and 32 is a flexible strip formedof an elastomeric material. The first arms 31 are adapted to bend whenportions of the second arms 32 are pulled into the tube 20. As a result,the two pairs of first arm 31 and second arm 32 move toward each otherwith an elastic force being stored. The elastic force may pull the pairsof first arm 31 and second arm 32 apart automatically when the pullingis removed.

In operation, one hand may press back the trigger handle 12 to pull thesecond arms 32 further into the tube 20 by moving the pairs of first arm31 and second arm 32 toward each other until an article (not shown) isgripped by the jaws 33.

Note that the jaw 33 may be shaped other than cup in other embodimentswithout departing from the scope and spirit of the invention as long asa secure gripping of an article is made possible by the jaws 33. Furthernote that the tube 20, the chuck 21, the first arms 32, and the jaws 33are well known devices.

Referring to FIG. 2, the lock section 10 further comprises a connectingmember 14, a link 15, and a locking plate 16. The connecting member 14is provided in the rear of the elongate tube 20 in the lock section 10.In detail, the elongate connecting member 14 has a rear end secured tothe trigger handle 12 and a front end secured to the second arms 32which have portions extended from the tube 20 to secure to the jaws 33.

Referring to FIG. 3, the pistol-shaped housing 11 consists of two matedhalves and comprises a forward channel 11 a, a first pivot pin 11 b, acurved groove 11 c, a second pivot pin 11 d, and an opening 11 e open toboth sides of the housing 11. The channel 11 a is adapted to retain therear of the tube 20. The first pivot pin 11 b is pivotably connected toan upper end of the trigger handle 12 such that the trigger handle 12 isable to pivot a predetermined angle about the first pivot pin 11 b. Thegroove 11 c is adapted to retain an upper part of the locking plate 16such that the locking plate 16 is able to pivot a predetermined angleabout the groove 11 c. The second pivot pin 11 d is pivotably connectedto the release member 13 such that the release member 13 is able topivot a predetermined angle about the second pivot pin 11 d. The opening11 e is adapted to allow parts of the release member 13 to project fromthe housing 11 for facilitate operation. Note that both the first andsecond pivots 11 b and 11 d pivotably connected to holes of the housing11 are well known in the art and a detailed description thereof istherefore deemed unnecessary.

Referring to FIGS. 4 and 5 in conjunction with FIG. 2, the triggerhandle 12 a slightly curved member and comprises an upper first aperture12 a, a passage 12 c below the first aperture 12 a, a well 12 b in anupper portion of the passage 12 c, and a cavity 12 d adjacent thepassage 12 c and being in communication with the passage 12 c through anaperture. The first pivot pin 11 b is inserted into the first aperture12 a so as to be pivotal about the housing 11. The link 15 has a forwardend secured to the well 12 b in the passage 12 c. The passage 12 c isadapted to receive an enlarged head 14 a of the connecting member 14.The cavity 12 d is adapted to receive a portion of a linking bar 14 b ofthe connecting member 14. The head 14 a is prohibited from entering intothe cavity 11 d because the aperture interconnecting the cavity 11 d andthe passage 12 c is smaller than the head 14 a.

Referring to FIG. 5 specifically, in addition to the rear head 14 a andthe intermediate linking bar 14 b the connecting member 14 furthercomprises a forward connection member 14 c. The connection member 14 cand most portion of the linking bar 14 are retained in the tube 20(i.e., in the channel 11 a). The connection member 14 c is secured tothe other ends of the second arms 32. In operation, pressing back thetrigger handle 12 will pull both the connecting member 14 and the secondarms 32 rearward.

Referring to FIG. 6, the slightly curved link 15 comprises a forwardmember 15 a secured to the well 12 b of the trigger handle 12, and tworear curved members 15 b each having an uneven upper face 15 c for thesake of increasing friction as detailed later.

Referring to FIG. 7, the rectangular locking plate 16 comprises a top 16b, a bottom 16 c, and two intermediate holes 16 a spaced apart by apredetermined distance. The holes 16 a are large enough to either allowthe curved members 15 b to freely pass or allow same to lockingly retaintherein. The locking plate 16 has a predetermined thickness. The top 16b is retained in the groove 11 c and the bottom 16 c is retained in therelease member 13 as detailed later.

Referring to FIG. 8, the release member 13 comprises two side plates 13a each having a laterally projecting release lever 13 b, a top hollowcylinder 13 c, a hooked base 13 d, and a slot 13 e between the plates 13a. The plates 13 a are mounted on inner surfaces of the housing 11 atboth mouths of the opening 11 e. The second pivot pin 11 d has adiameter slightly smaller than the bore of the cylinder 13 c. Thus, thesecond pivot pin 11 d is adapted to insert through the cylinder 13 c topivotably connect the release member 13 in the housing 11. The base 13 dis adapted to retain the bottom 16 c of the locking plate 16 and isadapted to allow same to pivot a predetermined angle. Thus, the lockingplate 16 may change an angle relative to the housing 11 as the releasemember 13 pivots. The slot 13 e is adapted to allow the curved members15 b to pass freely without interfering with the release member 13 inoperation.

Referring to FIG. 9, the locking plate 16 further comprises an upperface 16 d in each hole 16 a. Each of the curved members 15 b is adaptedto lockingly contact the upper face 16 d.

Referring to FIGS. 10 and 11 in conjunction with FIGS. 1 to 9, the top16 b of the locking plate 16 is retained in the groove 11 c and thebottom 16 c thereof is retained in the base 13 d. As stated above, therelease member 13 is pivotal about the second pivot pin 11 d. An articlegripping and locking operation of the invention will be described indetailed below. A user may use one hand to grip both the trigger handle12 and a fixed handgrip of the housing 11 and press the trigger handle12 backward. And in turn, the trigger handle 12 pivots counterclockwiseabout the first pivot pin 11 b. As such, the connecting member 14 andthe second arms 32 are pulled rearward. Also, the pairs of first arm 31and second arm 32 move toward each other until an article is gripped bythe jaws 33. At the same time, the link 15 secured to the trigger handle12 pivots counterclockwise about the first pivot pin 11 b. And in turn,the curved members 15 b freely move through the holes 16 b of thestationary locking plate 16 into the slot 13 e. Once the article isgripped by the jaws 33, the user may stop gripping the trigger handle 12or even remove the hand from the trigger handle 12. A forward force(i.e., the stored elastic force of the second arms 32) is immediatelyapplied to the trigger handle 12 to attempt to push the connectingmember 14 and the pairs of second arm 32 forward. However, the triggerhandle 12, the link 15, and the locking plate 16 remain stationary(i.e., locked) as detailed below. A potential clockwise pivotal movementof the curved members 15 b is prohibited since the engagements of theupper faces 15 c of the curved members 15 b with the upper faces 16 d inthe holes 16 a of locking plate 16 are lockingly tight due to the unevenupper faces 15 c (see FIG. 11). By configuring as above, once an articleis gripped a user does not have to worry about the article being droppedonto the ground after releasing the trigger handle since the article islocked automatically.

An unlocking operation (i.e., releasing the gripped article) of theinvention will be described in detailed below. A user may pivot therelease lever 13 counterclockwise (i.e., the release lever 13counterclockwise pivots about the second pivot pin 11 d). And in turn,the bottom 16 c of the locking plate 16 pivots counterclockwise aboutthe groove 11 c (see dash lines of FIG. 10). As such, the upper faces 15c of the curved members 15 b are disengaged with the upper faces 16 d ofthe holes 16 a in the locking plate 16. Once the curved members 15 b arefree, the forward force (i.e., the stored elastic force of the secondarms 32) is immediately applied to the trigger handle 12 and clockwisepivot both the link 15 and the trigger handle 12 in order to push theconnecting member 14 and the pairs of second arm 32 forward. As such,one pair of first arm 31 and second arm 32 move away from the other pairof first arm 31 and second arm 32. As a result, the article is no longergripped.

While the invention herein disclosed has been described by means ofspecific embodiments, numerous modifications and variations could bemade thereto by those skilled in the art without departing from thescope and spirit of the invention set forth in the claims.

1. A bar clamp comprising: a gripping section including two pairs offirst arm and second arm formed of an elastomeric material, and two jawseach formed at one ends of either pair of first arm and second arm; atube for receiving portions of the first arms and including a forwardchuck secured to the other ends of the first arms; and a housingincluding a forward channel with a rear portion of the tube securedtherein, a curved groove, a handgrip, a pivotal trigger handle, apivotal release member including two laterally projecting releaselevers, a hooked base, and an intermediate slot between the releaselevers, a connecting member in the rear portion of the tube and havingone end secured to the other ends of the first arms and the other endprojected rearward to secure to an intermediate portion of the triggerhandle, a rectangular locking plate having a top retained in the grooveand a bottom retained in the base, the locking plate including anintermediate opening, and a link having one end secured to theintermediate portion of the trigger handle and including a rear curvedlock member; whereby: pressing back the trigger handle willcounterclockwise pivot the trigger handle to pull the connecting memberand the second arms with an elastic force stored in the second arms,move pairs of first arm and second arm toward each other until anarticle is gripped by the jaws, and counterclockwise pivot the link tocause the lock member to move through the opening into the slot whereinthe article is gripped permanently after releasing the trigger handle bylockingly engaging a top of the lock member with an upper face of theopening; and counterclockwise pivoting the release lever willcounterclockwise pivot a bottom of the locking plate about the groove,disengage the top of the lock member with the upper face of the opening,release the elastic force and apply same to the trigger handle toclockwise pivot both the link and the trigger handle, and push theconnecting member and the pairs of second arm to move one pair of firstarm and second arm away from the other pair of first arm and second armfor dropping the article.
 2. The bar clamp of claim 1, wherein the topof the lock member has an uneven surface.
 3. The bar clamp of claim 1,wherein the lock member is a bifurcation including two branches.
 4. Thebar clamp of claim 3, wherein the opening comprises two holescorresponding to the branches for either allowing the branches to freelypass or lockingly retaining the branches therein.
 5. The bar clamp ofclaim 3, wherein a top of either branch has an uneven surface.